From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
Keith Busch <keith.busch@intel.com>,
Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
"Martin K. Petersen" <martin.petersen@oracle.com>
Subject: Re: [PATCH 8/9] nvme: implement multipath access to nvme subsystems
Date: Mon, 25 Sep 2017 17:07:20 +0200 [thread overview]
Message-ID: <20170925150720.GA11055@lst.de> (raw)
In-Reply-To: <55a10165-ac3c-f808-b031-6d907c314c30@suse.de>
On Mon, Sep 25, 2017 at 04:05:17PM +0200, Hannes Reinecke wrote:
> On 09/25/2017 03:50 PM, Christoph Hellwig wrote:
> > On Mon, Sep 25, 2017 at 03:47:43PM +0200, Hannes Reinecke wrote:
> >> Can't we make the multipath support invisible to the host?
> >> IE check the shared namespaces before creating the device node, and just
> >> move them under the existing namespaces if one exists?
> >
> > That was what my first version did, but various people talked me
> > out of it. Unfortunately just multiplexing breaks a few things,
> > including the userspace passthrough ioctls.
> >
> Care to give some specifics?
> How would userspace passthrough be affected?
Because specific commands will have to go to the right controller and
not just any avaiable controller. If we only expose a single node
for multipath there is no way to chose the specific one.
WARNING: multiple messages have this Message-ID (diff)
From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH 8/9] nvme: implement multipath access to nvme subsystems
Date: Mon, 25 Sep 2017 17:07:20 +0200 [thread overview]
Message-ID: <20170925150720.GA11055@lst.de> (raw)
In-Reply-To: <55a10165-ac3c-f808-b031-6d907c314c30@suse.de>
On Mon, Sep 25, 2017@04:05:17PM +0200, Hannes Reinecke wrote:
> On 09/25/2017 03:50 PM, Christoph Hellwig wrote:
> > On Mon, Sep 25, 2017@03:47:43PM +0200, Hannes Reinecke wrote:
> >> Can't we make the multipath support invisible to the host?
> >> IE check the shared namespaces before creating the device node, and just
> >> move them under the existing namespaces if one exists?
> >
> > That was what my first version did, but various people talked me
> > out of it. Unfortunately just multiplexing breaks a few things,
> > including the userspace passthrough ioctls.
> >
> Care to give some specifics?
> How would userspace passthrough be affected?
Because specific commands will have to go to the right controller and
not just any avaiable controller. If we only expose a single node
for multipath there is no way to chose the specific one.
next prev parent reply other threads:[~2017-09-25 15:07 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-25 13:40 nvme multipath support V3 Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-09-25 13:40 ` [PATCH 1/9] block: move REQ_NOWAIT Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-10-11 11:51 ` Sagi Grimberg
2017-10-11 11:51 ` Sagi Grimberg
2017-09-25 13:40 ` [PATCH 2/9] block: add REQ_DRV bit Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-10-11 11:51 ` Sagi Grimberg
2017-10-11 11:51 ` Sagi Grimberg
2017-09-25 13:40 ` [PATCH 3/9] block: provide a direct_make_request helper Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-10-11 11:54 ` Sagi Grimberg
2017-10-11 11:54 ` Sagi Grimberg
2017-09-25 13:40 ` [PATCH 4/9] block: add a blk_steal_bios helper Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-09-25 13:40 ` [PATCH 5/9] nvme: track subsystems Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-09-25 16:07 ` Keith Busch
2017-09-25 16:07 ` Keith Busch
2017-10-11 11:57 ` Sagi Grimberg
2017-10-11 11:57 ` Sagi Grimberg
2017-10-18 10:12 ` Christoph Hellwig
2017-10-18 10:12 ` Christoph Hellwig
2017-10-18 11:16 ` Sagi Grimberg
2017-10-18 11:16 ` Sagi Grimberg
2017-09-25 13:40 ` [PATCH 6/9] nvme: introduce a nvme_ns_ids structure Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-09-25 16:08 ` Keith Busch
2017-09-25 16:08 ` Keith Busch
2017-10-11 11:59 ` Sagi Grimberg
2017-10-11 11:59 ` Sagi Grimberg
2017-09-25 13:40 ` [PATCH 7/9] nvme: track shared namespaces Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-09-25 16:11 ` Keith Busch
2017-09-25 16:11 ` Keith Busch
2017-09-25 16:19 ` Christoph Hellwig
2017-09-25 16:19 ` Christoph Hellwig
2017-10-11 12:04 ` Sagi Grimberg
2017-10-11 12:04 ` Sagi Grimberg
2017-10-18 10:15 ` Christoph Hellwig
2017-10-18 10:15 ` Christoph Hellwig
2017-09-25 13:40 ` [PATCH 8/9] nvme: implement multipath access to nvme subsystems Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-09-25 13:47 ` Hannes Reinecke
2017-09-25 13:47 ` Hannes Reinecke
2017-09-25 13:50 ` Christoph Hellwig
2017-09-25 13:50 ` Christoph Hellwig
2017-09-25 14:05 ` Hannes Reinecke
2017-09-25 14:05 ` Hannes Reinecke
2017-09-25 14:45 ` Keith Busch
2017-09-25 14:45 ` Keith Busch
2017-09-25 15:07 ` Christoph Hellwig [this message]
2017-09-25 15:07 ` Christoph Hellwig
2017-09-25 16:18 ` Keith Busch
2017-09-25 16:18 ` Keith Busch
2017-09-28 15:53 ` Keith Busch
2017-09-28 15:53 ` Keith Busch
2017-09-29 14:21 ` Tony Yang
2017-09-29 14:21 ` Tony Yang
2017-10-01 8:07 ` Christoph Hellwig
2017-10-01 8:07 ` Christoph Hellwig
2017-09-30 19:37 ` Johannes Thumshirn
2017-09-30 19:37 ` Johannes Thumshirn
2017-10-01 8:07 ` Christoph Hellwig
2017-10-01 8:07 ` Christoph Hellwig
2017-10-02 6:19 ` Hannes Reinecke
2017-10-02 6:19 ` Hannes Reinecke
2017-10-11 12:24 ` Sagi Grimberg
2017-10-11 12:24 ` Sagi Grimberg
2017-09-25 13:40 ` [PATCH 9/9] nvme: also expose the namespace identification sysfs files for mpath nodes Christoph Hellwig
2017-09-25 13:40 ` Christoph Hellwig
2017-09-25 16:19 ` Keith Busch
2017-09-25 16:19 ` Keith Busch
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